Need some design help

[Gary_in_Indiana]

beenthere,

I've seen that kind of set up on mobile home toters around here. I like the idea of keeping the whole deal bobtail length. I like not having to involve a third piece of equipment (the dolly) and I like not dragging anything behind.

I'm very concerned, however, about the feasibility of temporarily affixing the ramps to the semi to haul a car or truck. I think that might just be begging for trouble. It sounds like a lot to ask of a driver, too.

 

[hazmat]

Gary,

Franz and I are on the same page. This tubing "frame" would rigidly attach to the tow dolly, converting it from "standard" trailer to a fith wheel.

If you've got a pic of the tow dolley I might be able to model something up on ProEngineer (CAD )for you. Been a little slow at work lately.

 

[Gary_in_Indiana]

Hazmat,

I now see the light (finally). Thanks to you and Franz for walking me through this concept.

I'll try to get some pictures of a tow dolly for you. I see some advertised quite often and will try to scan a picture from that unless you need a particular side or angle. Thanks so much for your generous offer of help with this. I really appreciate it.

 

[wroughtn_harv]

Morning Gary,

Let me offer another suggestion.

Let's completely forget the fifth wheel assembly. Let that puppy rest. It's been tugged till it's poor little tugger is probably closer to being a tuggette than a tuggor.

All tractors have a flanged channel cross piece at the back crossmember. Look at that and try to find some commonality.

What I'm thinking is two pieces made like capital "L"s turned up side down. The "L" with an attitude. You know then one that's waving part of it's hand up in the air parallel to the upright.

These two pieces sit upon the crossmember with the horizontal part of the "L" laying on top of the crossmember.

At the bottom of the upside down "L" have a clamping piece that picks up the bottom of the crossmember.

You want these two "L"s to be firmly attached to the crossmember.

Now on the vertical leg of the "L" you want a flange that holds a piece of two and a half inch quarter wall square tubing, reciever stock if you will. This needs to have two holes drilled vertically. One of these pieces on each "L".

Then you have a horizontal piece of two inch square quarter wall tubing for a crosspiece between the "L"s. This cross piece has a reciever hitch female attached.

What you have when you're done is an adjustable reciever hitch that fits on the crossmember of a tractor or cab and chassis. You then can pull a trailer or a dolly as you desire or even use a common tow bar assembly.

The whole thing can fit in a tool box for carrying and be up on in ten fifteen minutes with practice.

Hope this helps.

 

[Anonymous Poster]

Gary, now that you see the light, there's one question you might want to consider before you go to building. How smart is the driver yo're gonna send? I've seen guys who could set up anything in the dark at 10 below zero, and other drivers who couldn't figure out how to set up a soonerboomer to save their life.
Another possibility that comes to mind, if the tractor has a pintle hook on the rear x member, it might be a lot simpler to make a quick attach converter for the dolly toung.
If not, you could make up a clamp on hitch for the rear x on the tractor, like the old Uhaul or Reese rental hitches that used 2 hooks over the bumper and a pair of chainsto clamp the whole assembly to the bumper.

 

[hazmat]

I like Wharv's idea, more compact. Trick is to find the commonality of the different tracotor cross members.

Blue is the upsidedown L, Red is clamp. orange is reciever hitch.

 

[hazmat]

Another view

 

[hazmat]

Add a hole pattern to the orange part & it is adjustable for width. I would use pins to attach that part.

The clamps (red) would bolt to the L's (blue) and then one big honking bolt on the inside to keep it all together.

The clamps are slotted where they attach below the crossmember. With the right hole spacing on the L, you have infinite adjustment.

 

[hazmat]

Here is the Franz & Hazmat fifth wheel tow dolley concept.

You could break the blue part into as many pieces as you need to to make it manageable to assemble.

The other option is to make it rotate where it attaches to the tow dolley. pull a pin and swing it 180 degrees so that it faces backwards when you tow with the chase vehicle (instead of the truck). The verticle member would have to be round instead of square.

Yellow is a simple model of the tow dolley. the ball coupler would stick out in front of the fifth wheel adaptor.

 

[hazmat]

another view